• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.1
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• pp.43-49
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• 2007

The methods of physical oceanographic surveys to examine the effect of thermal discharge from nuclear power plants in Korea have been reviewed and a standard guide to the survey is proposed. It is desirable that in situ observation and numerical thermal diffusion modeling are conducted simultaneously to describe the variation in temperature distribution affected by thermal discharge from a power plant because any observation or numerical modeling alone has limits to do so quantitatively. It is suggested that the field observation must be based on the concept of heat budget modeling considering all artificial and natural heat sources/sinks around the power plant. Any results from numerical modeling must reach to a certain statistical significance level to use for a standard temperature distribution. In addition, the development of standard numerical codes is proposed to improve the problems shown in the past numerical circulation and diffusion modelling.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.04a
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• pp.91-98
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• 2000

Derivation of stage-discharge relationship and characteristics for Yangsan river is presented in this paper. This research has been conducted as the second one after the first trial of 1997. The determination of discharge at a Yangsan river gauging was best made by measuring the flow velocities with a current meter and rod float. The rating curve obtained through 52 stage-discharge measurements on Yangsan river basin in 1999 is represented by Q=15.3540-140.6076H+182.44372$H^2$, which is discovered to be most excellent among other curves in reliability analysis. The capability of the observed stage-discharge data for Yangsan river was tested by HEC-RAS program, and its capability to reproduce discharge was investigated and compared with the computational results. Rating curve stability is determined on the basis of deviations in the stage-discharge relationship, utilization of specific gauge, and absolute differences between sequential stream flow measurements and an analysis residuals. Therefore it seems necessary to research method to obtain rating curve in a rigorous and accurate manner.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.51-54
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• 2003

The spontaneous oscillations in the optogalvanic signals are observed in negative glow region of Ar hollow cathode discharge. The spontaneous oscillations in the optogalvanic signals are observed at low discharge currents less than about 3 mA. Based on the simultaneous measurements of both the density variation of metastable atoms and emission intensities of the 1s-2p transitions, one of the possible mechanisms for the spontaneous oscillation is considered to be related to the stepwise ionization of the metastable atoms due to collisions with slow electrons in the discharge.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.128-131
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• 2002

In this paper, we used the V-Q Lissajous‘ figure for studying on the plasma discharge characteristics of the 42 inches AC-PDP. From the V-Q Lissajous‘ figure, we could observe exactly the driving conditions that the self-erasing discharge takes place. At the time, the total wall charges lessened by self-erasing discharge was calculated quantitatively. Beside of the just observation of self-erasing discharge and calculation of the charges lessened, we could find out the optimum driving conditions for inducing the maximum wall charges accumulated on the dielectric layer with measuring the Wall voltage from the V-Q Lissajous' figure.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.597-600
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• 2007

The address and sustain discharge characteristics in plasma display panels (PDPs) are investigated and compared by the optical emission spectroscopy using the ICCD and Vt close-curve analysis. The observations on the xenon (Xe) emission show that the spatial and temporal evolutions in the first sustain discharge are quite different from those in the address and the other sustain discharges. The striation found in the conventional sustain discharge doesn't occur in the first sustain discharge. These different discharge behaviors are explained by employing the Vt close-curve.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1035-1042
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• 1998

After the 1990's, a computer-aided partial discharge(PD) measurement system was referred in part of aging diagnosis using digital signal processing as the new technology has been studied. The PD patterns and relevant information for pattern recognition are discussed in PD research area, because discharge quantity(q), the number of discharge pulse(n) and the applied boltage phase($\varphi$) was combined with the system information of the aging state. This paper investigates the discharge phase and quantity, as well as the number of discharge(n) with regard to discharge signals generated in power cable. therefore, according to characteristic analysis on the distribution of $\varphi$, q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

• Journal of Hydrogen and New Energy
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• v.9 no.4
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• pp.135-141
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• 1998

The effects of heat-treatment on discharge characteristics of $TiFe_{1-x}Ni_x$ alloy were investigated. The content of Ni in alloy was varied from x = 0.1 to 0.6 by each 0.1 increment. Discharge capacity change of each alloy with C/D cycles was measured. With increasing Ni-content initial discharge capacity was increased. but at x = 0.6 it was deceased again. With increasing C/D cycles discharge capacity was rapidly decreased in the alloy of high Ni-content. In order to investigate the effects of heat-treatment on cycle life, $TiFe_{0.5}Ni_{0.5}$ alloy having maximum initial discharge capacity was heat-treated at various temperatures in the range of $700{\sim}900^{\circ}C$ and tested. The loss of initial discharge capacity was appeared at all temperatures. but cycle characteristics of the alloy was improved. The electrodes heat-treated for 1 hour in the range of $700{\sim}850^{\circ}C$ showed good recovery of discharge capacities through repeated cycles, and from SEM observation results these were considered as 1 hour in the range of $700{\sim}850^{\circ}C$ showed good recovery of discharge capacities through repeated cycles, and from SEM observation results these were considered asbeing due to increased electrode strength and small loss of porosity during heat-treatment. The electrode heat-treated for 1 hour at $900^{\circ}C$ showed poor discharge characteristics because of low porosity.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.393-400
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• 2011

In a large scale survey, cluster sampling design in which a set of observation units called clusters are selected is often used to satisfy practical restrictions on time and cost. Especially, a two stage cluster sampling design is preferred when a strong intra-class correlation exists among observation units. The sample Primary Sampling Unit(PSU) and Secondary Sampling Unit(SSU) size for a two stage cluster sample is determined by the survey cost and precision of the estimator calculated. For this study, we derive the optimal sample PSU and SSU size when the population SSU size across the PSU are di erent by extending the result obtained under the assumption that all PSU have the same number of SSU. The results on the sample size are then applied to the $4^{th}$ Korea Hospital Discharge results and is compared to the conventional method. We also propose the optimal sample SSU (discharged patients) size for the $7^{th}$ Korea Hospital Discharge Survey.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.9
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• pp.870-875
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• 2005

We measured the optogalvanic signal and discharge voltage-current(V-I) curve under the two different discharge conditions with different buffer gases, Ar, and Ne. When the Gd was used as a cathode material at low discharge current less than 10mA, a significant change was observed in the current-voltage curve. Time resolved optogalvanic signal measurement were measured by the diode laser of which wavelengths correspond to metastable transition line of these gases (Ar, Ne). From these measurements, we found that the characteristics of the V-I curve strongly depend on the Penning ionization process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.488-491
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• 2002

We report the observation of line shapes in the optogalvanic spectrum, which are different from those of absorption, for transitions origination from the $3P_2$ ($1s_5$ in Paschen notation) metastable level of argon. The OG line shapes resemble those of absorption and be used to diagnose the characteristics of the discharge plasma. The measured plasma temperatures of Ar hollow cathode discharge for several metal cathodes are about 620~780K at discharge current of 7~10mA.